package com.iot.inter.utils;
import javax.xml.bind.*;
import javax.xml.namespace.QName;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.Collection;

/**
 * 使用Jaxb2.0实现XML<->Java Object的Binder.
 * 特别支持Root对象是List的情形.
 */
public class JaxbUtil {
	//多线程安全的Context.
	private JAXBContext jaxbContext;

	/**
	 * @param types 所有需要序列化的Root对象的类型.
	 */
	public JaxbUtil(Class<?>... types) {
		try {
			jaxbContext = JAXBContext.newInstance(types);
		} catch (JAXBException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Java Object->Xml.
	 */
	public String toXml(Object root, String encoding) {
		try {
			StringWriter writer = new StringWriter();
			createMarshaller(encoding,false).marshal(root, writer);
			return writer.toString();
		} catch (JAXBException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Java Object->Xml, 特别支持对Root Element是Collection的情形.
	 */
	public String toXml(Collection<?> root, String rootName, String encoding) {
		try {
			CollectionWrapper wrapper = new CollectionWrapper();
			wrapper.collection = root;
			JAXBElement<CollectionWrapper> wrapperElement = new JAXBElement<CollectionWrapper>(new QName(rootName),
					CollectionWrapper.class, wrapper);
			StringWriter writer = new StringWriter();
			createMarshaller(encoding,false).marshal(wrapperElement, writer);
			return writer.toString();
		} catch (JAXBException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Xml->Java Object.
	 */
	@SuppressWarnings("unchecked")
	public <T> T fromXml(String xml, String encoding) {
		try {
			ByteArrayInputStream xmlStream = new ByteArrayInputStream(xml.getBytes(encoding));
			//StringReader reader = new StringReader(xml);
			return (T) createUnmarshaller().unmarshal(xmlStream);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 创建Marshaller, 设定encoding(可为Null).
	 */
	public Marshaller createMarshaller(String encoding,boolean omitFragment) {
		try {
			Marshaller marshaller = jaxbContext.createMarshaller();

			marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.FALSE);
			marshaller.setProperty(Marshaller.JAXB_FRAGMENT, omitFragment);// 是否省略xml头声明信息
			if (null!=encoding&&!"".equals(encoding)) {
				marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
			}
			return marshaller;
		} catch (JAXBException e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * 创建UnMarshaller.
	 */
	public Unmarshaller createUnmarshaller() {
		try {
			 
			Unmarshaller unmarshaller=jaxbContext.createUnmarshaller();

			return unmarshaller;
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * 封装Root Element 是 Collection的情况.
	 */
	public static class CollectionWrapper {
		protected Collection<?> collection;
	}


    @SuppressWarnings("unchecked")
    public <T> T fromXML(String fileName) {
        return (T)fromXML(new File(fileName));
    }


    @SuppressWarnings("unchecked")
    public <T> T fromXML(File file) {
        try {
            Unmarshaller unmarshaller = createUnmarshaller();
            return (T) unmarshaller.unmarshal(file);
        } catch (JAXBException e) {
            throw new RuntimeException(e);
        }
    }


    @SuppressWarnings("unchecked")
    public <T> T fromXML(InputStream stream) {
        try {
            Unmarshaller unmarshaller = createUnmarshaller();
            return (T) unmarshaller.unmarshal(stream);
        } catch (JAXBException e) {
            throw new RuntimeException(e);
        }
    }
    
}